An expression is a sequence of operators and operands that specifies computation
of a value. An expression may consist of single entity or some combination of
such entities interconnected by one or more operators. All expression represents
a logical connection that's either true or false. Thus logical type expression
actually represents numerical quantities.
In C every expression evaluates to a value i.e., every expression results in
some value of a certain type that can be assigned to a variable. Some examples
of expressions are shown in the table given below.